1. Field of the Invention
The invention relates to one or more optical networking components. In particular, the invention relates to optical components having a reflecting surface.
2. Background of the Invention
Many optical components include one or more surfaces where light signals are reflected. For instance, many optical components include waveguides that intersect. A reflecting surface is often formed at the intersection for reflecting light signals from one waveguide into the other waveguide. The position and profile of the reflecting surface relative to the waveguides should be precise in order to ensure reflection of the light signals in the desired direction.
A reflecting surface, at the intersection of the waveguides is often formed by performing two sequential mask and etch steps. The limitations of photolithography mask printing equipment prevents precise alignment of two sequentially formed masks. As a result, the portion of the reflecting surface formed during the first etch is often not aligned with the portion of the reflecting surface formed during the second etch. Accordingly, the portion of the reflecting surface formed during the first etch has a different position relative to the waveguides than does the portion of the reflecting surface formed during the second etch. The inconsistent positioning of the reflecting surface reduces the performance quality of the optical component.
For the above reasons, there is a need for a component having a reflecting surface with an accurate position relative to the waveguides.
The invention relates to a method of forming an optical component. The method includes forming a first mask so as to protect a ridge region of a light transmitting medium. The ridge region is a region of the light transmitting medium a region where a ridge of a waveguide will be formed. The method also includes performing a first etch of the light transmitting medium so as to form a first side of the ridge. The first mask serves to define a profile of the first side of the ridge during the first etch. The method further includes performing a second etch of the light transmitting medium so as to form a second side of the ridge. The first mask also serves to define a profile of the second side of the ridge during the second etch. In some instances, the second side is formed so as to have a different height than the first side.
The invention also relates to a method of forming a reflecting surface on an optical component. The method includes forming a first mask so as to protect a ridge region of a light transmitting medium. The ridge region is a region where a ridge of a waveguide will be formed. The method also includes performing a first etch of the light transmitting medium so as to form a side of the ridge. The first mask defines a profile of the side of the ridge during the first etch. The method further includes performing a second etch of the light transmitting medium so as to form the reflecting surface. The first mask defines a profile of the reflecting surface during the second etch.
In one embodiment of the invention, the second etch is performed before the first etch.
In another embodiment of the invention, the second etch is performed more deeply than the first etch. Accordingly, the reflecting surface is taller than the side of the ridge.